Kipp&Zonen BSRN Scientific Solar Monitoring System - Manual (Page 30)

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In locations where a site is presently located, this inform ation should be present with the required
accuracy.
Global Positioning System (GPS) technology can provide the site location to within 30 m without
correction and to better than 5 m with corrected system s. Elevation can also be accurately
determ ined from GPS. For a new site, this technology m ay be the easiest and m ost accurate
m eans of determ ining its location.
3.1.4 General site description for the Archive
A second aspect of describing the site location is a general description of the surrounding area.
The Technical Plan for BSRN Data Managem ent (TPBDM), Version 2.1, defines two fields for the
description of each site. The first field is surface type, while the second field is topography type.
These fields are further described in Tables 4.14 and 4.11, respectively, of the TPBDM and are
included as elem ents in logical record four of the station-to-archive file form at. The tables are
reproduced below as Table 3.1 and Table 3.2 for convenience. The form at for each descriptor is
I2.
W hile these tables are useful, they rem ain lim ited in describing the site fully because few sites fall
easily into any sim ple set of categories as described. To aid researchers in understanding the
overall com plexity of the area surrounding a station, a m ore com plete description, including
topographic m aps and photos of the site and its surroundings, is required.
3.2. BSRN Station Information Document
W hile the Archive inform ation provides a brief description of the site and the site survey provides
inform ation on obstructions to the incom ing radiative fluxes, if any, a m ore thorough description is
necessary for data users. Individuals involved in the determ ination of clim ate change over tim e or
the validation of satellite algorithm s require detailed inform ation about the site surroundings to
determ ine the quality of the data for their specific needs. For exam ple, individuals studying clim ate
change require not only a knowledge of the general topography, but also details of city growth,
changes in land use, farm ing techniques if in an agricultural area or flight patterns and frequency if
near an airport over the tim e period of the m easurem ents. Sim ilarly, those using the data to obtain
vicarious calibrations of satellite-borne instrum ents require sim ilar knowledge to determ ine how
representative the site is with respect to its surroundings. To provide this inform ation, a m ore
com plete site description is required. The docum ent, as described, has been m odelled after a
sim ilar one designed for the Com m ission Internationale de l’Éclairage (C IE) International Daylight
Measurem ent Program m e.
Data in relation topography type
Value Topographic Feature Population Density
1 flat urban
2 flat rural
3 hilly urban
4 hilly rural
5 m ountain top urban
6 m ountain top rural
7 m ountain valley urban
8 m ountain valley rural
Table 3.1. Topography types used in archive site identification.